By: James R. Allen IIII
Many trees in our managed landscapes are valued for their unique growing habit, such as an open spreading canopy, or a narrow upright branching in small spaces. Although aesthetically pleasing, these growth habits can have inherent problems that require support systems to keep them, safe and structurally sound.
One of the most common methods used to sure up these problems is tree cabling. This involves the installation of a steel cable in the upper two-thirds of a tree’s canopy to help support an out-stretched limb, or a leader hanging precariously over a house. The cable transfers the load from itself to an adjacent limb, therefore not taking on the full weight, and reducing the risk of breaking away.
There are basically three main reasons to add tree cabling to your landscape trees. The first is to prevent splitting of a healthy tree or limb. The second is to restore a damaged tree due to previous breakage, and the third is to mitigate possible hazards in a public area.
The first step in tree cabling is to identify the hazard potential of the tree and its risk to nearby people or structures. This is identified by tree characteristics such as included bark, or defective unions, large multi-stemmed trees, such as Silver Maple and River Birch, or top heavy limbs on a specimen tree. Next it should be identified if the tree is a candidate for cabling. Is the tree too far gone? Is there enough solid wood to attach a cable? These are questions that a certified arborist can assist in answering.
Although this is a common practice used in the landscape, there are risks involved.
For one, tree cabling will cause a small wound in the tree where the lag bolt is installed, but in most cases the tree will heal around. Secondly there is not guarantee against limb, or tree failure with cabling, this is simply a best management practice reduce the risk of failure. Also, be prepared to have the cables inspected yearly to ensure that they are intact or possibly replaced as the tree ages and increases in size.
These are considered acceptable risks when valuable specimen trees are involved, and tree cabling is a better alternative to complete tree removal.